Too Rare to Learn: Prescribed Cyclone Tracks Degrade a Bay of Bengal Ocean Emulator

📅 2026-09-03
📈 Citations: 0
Influential: 0
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🤖 AI Summary
研究发现,在孟加拉湾海洋模拟器中,将飓风路径作为预设输入会因信号稀有导致模型表现下降,提出移除该输入以改善预测。
📝 Abstract
Neural ocean emulators are being proposed for regional forecasting in cyclone-exposed coastal seas, and a natural design choice is to hand the network the cyclone as a prescribed input. We test that choice in the Bay of Bengal and find it harmful. We withhold 15 whole cyclones spanning 65 to 150 kt from GLORYS12 reanalysis and compare two U-Nets that are identical except for four prescribed cyclone-track channels. Across three seeds the ocean-only model beats persistence in every run and the storm-conditioned model loses to it in every run, with the two skill ranges disjoint (p = 3.1e-5, paired across storms). The cause is exposure frequency rather than signal content: the channels are non-zero on only 7.9% of training days, so they are out of distribution the moment they activate. The extra error falls inside the prescribed storm footprint, and replacing the real cyclone map with a no-storm map at inference improves held-out storm forecasts by 7.5 to 16.4% in every seed. The conditioned network has learned a response to a rare signal that is confidently wrong.
Problem

Research questions and friction points this paper is trying to address.

neural ocean emulators
cyclone-exposed coastal seas
prescribed input
exposure frequency
out of distribution
Innovation

Methods, ideas, or system contributions that make the work stand out.

Neural Ocean Emulator
Cyclone Track
Exposure Frequency
Bay of Bengal
Out-of-Distribution
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S
Sumaiya Islam
Department of Software Engineering, University of Dhaka, Dhaka, Bangladesh